Electric equipment for mining machines



A ril 11, 1933.v N. D. LEVIN ET AL ELECTRIC EQUIPMENT FOR MINING MACHINES Filed Oct. 18, 1928 Io/m 5. 56/7121 417 4 m5; \rujoE. w

Patented Apr. 11, 1933 UNITED STATES PATENT OFFICE MANUFACTURING COMPANY, OF COLUMBUS, OHIO, A CORPORATION OF OHIO ELECTRIC EQUIPMENT FOR MINING MACHINES Application filed October 18, 1928. Serial No. 313,323.

The present invention relates to certain new and useful improvements in electric equipment for mining machines, and especially to an improved arrangement of parts T forming the electric circuits of locomotives,

self-propelling trucks, and similar apparatus adapted for use in coal mines subject to the accumulation of explosive gases in the working rooms of the mine.

The especial object of this invention is to provide a locomotive, or other mining appara-tus, adapted to receive its actuating electric current from a naked trolley wire in the usual and well known manner, when traveling 1 along the entries of the mine, or through a flexible conductor cable when operating in places subject to gas accumulations, and having automatically acting means to insure against the formation of arcs exposed to con- $9 tact with the gaseous atmosphere of the mine.

A further object is to provide in apparatus of the class described such an arrangement of parts that the operator will at all times be fully protected from electric shock.

The means whereby we attain these and other objects are fully set forth in the following specification and illustrated in the accompanying drawing which is a diagram of the electric circuits of a locomotive embodying our present invention, the several elements of the machine being indicated by appropriate symbols.

As heretofore constructed such apparatus have possessed certain inherent defects which seriously restrict their use in coal mines subject to accumulations of explosive gases. Motors, controllers, switches, fuses and the like, have been enclosed in explosion proof casings, and the supply of actuating current 49 has been maintained through flexible conductor cables connected with the supply conductors of the mine in a manner and at points conducive to safety. It has heretofore been customary and convenient to arrange the motor controlling devices between the supply conductors and the motor in order that the electric circuits may be disconnected from line potential to thereby protect the operator when making adjustments and repairs. By this arrangement there is full line potential between the electrical parts of the controller and its supporting frame and easing which, being attached directly to the frame of the machine and consequently with the ground, produces a tendency to destructive short circuits.

Explosive mixtures of gases are seldom encountered in the main haulage entries of a mine because of the strong currents of air flowing therethrough. The use of naked trolley wires, contacting trolley wheels, and ground returns through the rails of the mine track is therefore permissible in these portions of a mine, and because of their convenience are preferable for use. In rooms, where the principal mining operations are conducted, the ventilation is often imperfect and accumulations of explosive gases are of such frequent occurrence that every precaution must be taken to avoid the formation of electric arcs which might ignite such gases if present. c

In the drawing we have diagrammatically shown a locomotive having grounded frame F and thereon two motors adapted to propel the machine along the rails of a mine track. As here shown the motors comprise the armatures 1 and 2 and the field coils 3 and 4 which are connected by suitable conductors with a controller having a commutating cylinder 5 and a reverse cylinder 6, a metallic controller casing being shown diagrammatically at C, the casing being grounded on the frame F. Each of the cylinders is provided with contact plates adapted to establish connections with appropriate contact fingers in the usual and well understood manner to connect the conductors into suitable circuits for the desired operation of the motors. Resistance for the control of the current flowing through the motors is indicated at 7. A trolley wheel 8 is adapted to contact with the trolley wire 9 in the usual manner to supply the actuating current while operating in the entries of the mine. A cable reel 10 equipped with a double conductor flexible cable 11 is provided for use in the rooms, and other parts of the mine subject to accumulations of gas, and a motor 12 1s arranged to rotate the cable reel in a cable winding direction. Five solenoid switches 13,

1 N ILS D. LEVIN AND JOHN S. BELTZ, OF COLUMBUS, OHIO, ASSIGNORS TO THE JEFFREY I 14, 15, 16 and 17 are arranged in the main conductors of the circuits, and each is provided with an actuating coil 18, 19, 20, 21 and 22 respectively, arranged to close their respective switches. Two overload relays having switch members 23 and 24 arranged in the control circuit of the switches 16 and 17 are provided with coils 25 and 26, in series with the motor circuits and are energized by excessive currents therein to open their re- I spective switches. Resetting coils 27 and 28 are also provided to recl-ose the switches 23 and 24. 4

Having now described the general arrangement of parts we will point out more particularly the features of improvement which characterize our invention.

\Vhen the trolley wheel 8 is placed in con tact with the trolley wire 9 connection is established through the conductor 29 with the switch 15 which normally stands open. Current flowing through the conductor30, the actuating coil 20 and the conductor 31 to ground 32 formed on the "frame of the locomotive, energizes the coil 20 to close theswitch 15 sending current through the conductor 33, overload coil 25 and conductor 34 to the switch'16 which stands normally open. At the same time current flowing through the conductor 35, actuating coil 18 and conductor 36 to the ground 32 energizes the coil18 to close the switch 13 establishing connection between the ground. 32 through the conductor 37, the terminal 38 of the controller, the blow-out magnet 39 and the contact finger 40 with the contact segment 41 of the commutating cylinder 5 with which said finger is in permanent connection. The finger 42 of the controller is connected by a conductor 43 through the resetting coils 27 and 28 of the'overload relay to establish connection with the main positive conductor 33. When the controller cylinderis moved in the starting direction the finger 42 contacts with the corresponding segment 44 of the commutating cylinder to complete-the circuit and energize the coils 27 and 28 to cause the switch blades 23 and 24 to be moved to their closed position. This establishesa connection between the positive conductor 33 through the switch members 23 and 24, the conductor 45, the actuating coils 21 and 22 of the switches 16 and 17, and the conductor 46 to the finger 47 of thecontroller. A further movement of the commutating cylinder 5 establishes connection between the finger 47 and the contact segment 48 to complete the circuit to energize the coils 21 and 22 to close the switches 16 and. 17, thereby establis'hing connection through the conductor 49 between the main positive conductor 29 and the finger J of the'reverse cylinder of the controller. It is to be noted that the contact segment 48 is of such proportion that connecti'on 1S maintained between it and the finger 47 in all operative posltions of the commutating cylinder, and that by this connection the coils 21 and 22 are continuously energized to maintain the switches 16 and 17 in closed position. When the commutating cylinder 5 is turned in the reverse direction interrupting the connection between the finger 47 and the contact segment 48 the two switches 16 and 17 simultaneously open thereby dividing the arc and reducing the tendency to injury of the contact members. It is also to be noted that the proportions of the contact segments 41 and 71 are such that contact is not broken between these segments and the brushes 40 and 72 when the controller cylinder is moved to the off position, and the intermediate segments so overlap that the resistance circuit is never broken, thereby avoiding the formation of electric arcs in the controller.

When the reverse cylinder 6 is in position to cause the contact plates in the row marked PA to engage the appropriate fingers, connections will be established by which the motors are arranged in parallel, their armatures revolving in a direction to propel the locomotive ahead. When the reverse cylinder6 is turned to a position to cause the contact plates in the row marked SA. to engage the appropriate fingers, connections will be established by which the motors are arranged in series, their armatures revolving in a direction to propel the locomotive ahead. When the reversecylinder 6 is turned to a position to cause the contact plates in the row marked SR to engage the appropriate fingers, connections will be established by which the motorsare arranged in series, their armatures revolving in a direction to propel the locomotive rearwardly, or reverse. When the reverse cylinder 6 is turned to a position to cause the contact plates in the row marked PR to engage the appropriate fingers, connection will be established by which the motors are arranged in parallel, their armatures revolving in a direction to propel the locomotive in reverse. Further rotation of the commutating cylinder 5 connects more or less resistance in the circuits of the motor to control the speed of rotation of their armatures. As such devices are well understood in the mining machine art further description is not thought to be required at this time. i

VVhenthe locomotive is to be operated in a mine room, or similar location, and'must derive its actuating current through the flexible conductor cable 11, the conductor 50 is connected by a suitable hook 51 with the trolley wire 9, and the conductor 52 is connected by a suitable hook 53 with the track rail 54 in the entry thereby establishing con nection from the trolley wire 9 through the conductor 50, positive connection 55 of the cable reel, and the conductor56 to the switch 14 which-stands normally open. At the same time connections are established from the track rail 54 through the conductor 52, the negative connection of the cable reel 57, the conductors 58 and 37 to the terminal 38, blowout coil 39 and finger 40 of the commutating cylinder 5 of the controller. When the trolley wheel 8 is removed from contact with the trolley wire 9, current is cut off from the conductors 30 and 35 thereby de-energizing the coils 18 and 20 permitting the switches 13 and 15 to open. The switches 13, 14 and 15 are preferably provided with interlocking mechanism such that when the switches 13 and 15 are closed the switch 14 is locked open and when the switch 14 is closed the switches 13 and 15 are locked open. By this arrangement we have assured the exclusion of electric potential from the locomotive frame 32 and from the naked trolley wheel 8 while current is being received through the flexible conductor cable 11, affording added insurance against accidental short circuit between the naked trolley wheel and the machine frame, or shock to the operator.

When the commutating cylinder 5 is moved in the starting direction contact is established, as before described, between the finger 42 and contact plate 44 assuring the closing of the switch blades 23 and 24. Further movement of the commutating cylinder 5 establishes connection between the finger 47 and segment 48 to complete the circuit through the actuating coils 21 and 22 to close the switches 16 and 17 in the main positive conductors.

Because of the danger of injury to the cable 11 resulting from the operation of the locomotive at excessive speed, it is desirable that the motors of the locomotive shall be operated only in series when drawing current through the flexible conductor cable 11. To insure such operation we have provided upon the reverse cylinder 6 of the controller a contact plate 59 adapted, whenthe reverse cylinder is in either the series ahead or series reverse position, to contact with the fingers 60 and 61. The finger 60 is connected by a conductor 62 with the main positive conductor 56, and the finger 61 is connected through the conductor 63, the actuating coil 19 and the conductor 64 with the main negative conductor 58 thereby completing the circuit whereby the actuating coil 19 is energized to close the switch 14, completing the circuit from the trolley wire through the cable 11 and the locomotive motors to ground upon the track rail 54 in the entry, after which the speed of the locomotive may be controlled by manipulation of the commutating cylinder 5 in the usual and well known manner.

It is obvious that actuation of the motor 12 is required only when the locomotive is traveling in the reverse direction and when current is being received through the flexible conductor cable 11. To insure such operation we have provided a contact plate 65 upon the reverse cylinder so positioned that when the cylinder stands in the series reverse position the contact fingers 66 and 67 will be connected. The finger 66 is connected by a conductor 68 with the main negative conductor 37 and the finger 67 is connected through the conductor 69, the motor 12, conductors 70 and 62 to the main positive conductor 56 thereby establishing a circuit for energizing of the motor 12.

hat we claim is:

1. In a motor control system, a motor, a controller including a commutating cylinder, a resistance unit, contact portions on said cylinder cooperable with associated sta tionary contact fingers to cut in or out sections of said resistance unit to vary the currents applied to said motor, the extreme ones of said contact portions being in contact with their associated contact fingers in the zero position of the cylinder and all of said contact portions being interconnected and disposed to maintain a closed resistance circuit at the controller in all positions of the cylinder, a main line switch remote from the controller, and means operated in dependence upon movement of the cylinder from zero position and prior to the initiation of commutating action to close said line switch and maintain it closed as the cylinder is moved in either direction throughout its commutating positions.

2. In a motor control system, a motor, a controller including a commutating cylinder, a resistance unit, contact segments on said cylinder cooperable with associated station ary contact fingers to cut in or out sections of said resistance unit to vary the current supplied to said motor, a contact segment on the cylinder adapted to engage a main line contact finger in all positions of the cylinder, all of said segments being interconnected and so disposed as to maintain a closed resistance circuit at the controller in all positions of the cylinder, a main lineswitch, electro-magnetic means for closing said switch, a circuit for energizing said electro-magnetic means, an overload relay including a coil interposed in the main line and a switch member in said energizing circuit, an electro-magnetic reset device for said relay, means operable upon initial movement of said cylinder from zero position to energize said reset device, and switch means in said energizing circuit closed upon further movement of said cylinder and before the latter reaches its first commutating position.

3. In a motor control system, a motor, a controller including a commutating cylinder, a resistance unit, contact segments on said cylinder cooperable with associated stationary contact fingers to cut in or out sections of said resistance unit to vary the current supplied to said motor, a contact segment on the cylinder adapted to engage a main line contact finger in all positions of thecylinder, all of said segments being interconnected and so disposed as to maintain a closed resistance'circuit at the controller in all positions of the cylinder, a main line switch, electro-magnetic means for closing said switch, a circuit for energizing said electromagnetic means, an overload relay including a coil interposed in the main lineand a switch member in said energizing circuit, an electro-magnetic reset device for said relay, a contact segment on said cylinder and a fixed contact'finger brought into contacting rela:

tion upon initial movement of said cylinder from zero position to complete a circuit to said reset device, and a contact segment on said cylinder and a fixed contact finger brought into contacting relation upon further movement of said cylinder to complete said energizing circuit before the cylinder reaches its first commutating position.

4. Ina motor control system, a motor, a controller including a commutating cylinder, a. resistance unit, contact segments on said cylinder cooperable with associated stationary contact fingers to cut in or out sections of said resistance unit to vary the current suppliedto said motor, a contact segment on the cylinder adapted to engage a mainline contact finger in all positions of the cylinder, all of said segments being interconnected and so disposed as to maintain a closed re sistance circuit at the controller in all positions of' the cylinder, a main line switch, electro-magnetic means for closing said switch, an energizing circuit for said electromagnetic means, an overload relay including a coil interposed in the main line and a switch member in said energizing circuit, an electro-magnetic reset device for said relay, a contact segment on said cylinder and a fixed contact finger brought into contacting relation upon initial movement of said cylinder from zero position to complete a circuit to said reset device, and a contact segment on said cylinder and a fixed contact finger brought into contacting relation upon further movement of said cylinder to complete said energizing circuit before the cylinder reaches its first commutating position, said last named contact elements being so related as to remain in contact in all commutating positions of the cylinder.

5. In apparatus of the class described, a metallic frame, an electric supply line-having one of its sides in connection with said frame, a controller on said frame including contacts in connection with said frame and a conductive structuralelement grounded on said frame adjacent said contacts, a motor on said frame and having one side in connection with said controller, a connection between the other side of the motor and the other side of the line, and a switch in said-connection, said controller including a movable element adapted upon preliminary movement to close said switch.

6. In apparatus of the class described, a metallic frame, an electric supply line having one of its sides in connection with said frame, a controller on said frame including contacts in connection with said frame and a conductive structural element grounded on said frame adjacent said contacts, a motor on said frame and having one side in connection with said controller, a connection between the other side of the motor and the other side of the line, an electro-magnetic switch in said connection, an energizing circuit for said switch, an overload relay having a coil in said connection and a movable element bridging a gap in said circuit, areset circuit for said relay, said controller including a movable element, and means adapted upon an initial preliminary movement of said element to close said reset circuit and upon a further preliminary movement to complete said energizing circuit to close said switch.

7. In apparatus of the class described, a supply line comprising a track and an overhead conductor of negative and positive polarity respectively, a metallic frame movable in contact with said rail, a controller on said frame including contacts in connection with said frame and aconductive structural element grounded on said frame adjacent said contacts, a motor on said frame and having one side in connection with said controller, a trolley carried by said frame and contact ing with said overhead conductor, a connection between the trolley and the other side of the motor, and a switch in said connection, said controller including a movable element adapted upon preliminary movement to close said switch.

8. In apparatus of the class described, a supply line comprising a track andan overhead conductor of negative and positive polarity respectively, a metallic frame movable in contactwith said rail, a controller on said frame including contacts in connection with said frame and a conductive structural element grounded on said frame adjacent said contacts, a motor on said frame and having one'side in connection with said controller, a trolley carried by said frame and contacting with said overhead conductor, a connection between the trolley and the other side of the motor, an electro-magnetic switch in said connection, an energizing circuit for said switch, an overload relay having a coil in said connection and a movable element bridging a gap in said circuit, a reset circuit for said relay, said controller including a movable element, and means adapted upon'an initial preliminary movement of said element to close said reset circuit and upon a further preliminary movement to complete said energizing circuit to close said switch.

9. In a motor control system, a motor, a controller including a commutating cylinder, a resistance unit, contact portions on said cylinder cooperable with associated stationary contact fingers to cut in or out sections of said resistance unit to vary the current flowing through said motor, the extreme ones of said contact portions being in contact with their associated contact fingers in the zero position of the cylinder and all of said contact portions being interconnected and disposed to maintain a closed resistance circuit at the controller in all positions of the cylinder, a main line switch remote from the controller, and means operated in dependence upon movement of the cylinder from zero position and prior to the initiation of commutating action to close said line switch and maintain it closed as the cylinder is moved in either direction throughout its commutating positions, the controller and line switch being disposed at opposite sides of the motor, the controller being on the negative side and the line switch on the positive side thereof.

In testimony whereof We have hereunto set our hands.

NILS D. LEVIN. JOHN S. BELTZ. 

